Good interviewers are analysts of human behaviour and can tell when a person might be deceiving them, says “the lie guy”, Steve Van Aperen. It’s actually very difficult for the average person to lie, says Van Aperen, who has trained with the FBI and other investigative authorities, and conducted both employment and criminal interviews.

Lying requires a lot of effort, because “when delivering a deception, we’re trying to think of what we want to say and make it sound believable or credible”, whereas telling the truth is much easier because a person can rely on their memory. But while it’s difficult to structure and deliver a lie, it’s also hard for an untrained person to detect one. “Why? Because we listen to the content of what people say without paying attention to the other parameters.”

Lying in interviews
People will only tell you what they want you to know – they’ll edit the information they give you, Van Aperen warns. About a third of applicants lie on their CVs, he says, “which shouldn’t surprise anyone. If I’m competing against 20 other candidates, I want to look like I’m the best candidate.” He says that if you ask a candidate why they left their last job and they respond that the details are in their CV, “never, ever accept that”.

“It’s what we call ‘lying by referral’. It’s much easier for me to sit in front of a word processor and have poetic licence to type whatever I like, than what it is to lie to somebody, face to face.”

Body language
Good interviewers, Van Aperen says, are “vigilant at observing behaviours”. Usually when someone is being deceptive, there is a conflict or contradiction between what their mouth is saying and what their body is displaying. (It’s very difficult, for example, to answer a question truthfully by saying ‘yes’ while shaking your head in the negative.)

Interviewers should “look for changes or things that don’t look in place”, Van Aperen says, and look for “groups or clusters of body language rather than one-offs”.

When people are being deceptive, he says, they might:

• fidget or change their position;
  
• sit back in their chair;
• cross their arms and/or legs;
• avoid eye contact;
• lick their lips;
• increase their blink rate; or
• go into ‘lock down’ and avoid movement.

“Hand-to-face gestures are a really good indicator that people are saying something they think they shouldn’t be saying,” he says. “Watch for those, and often at the last moment there will be a diversion.”

Children find it natural to cover their mouths when telling a lie, “but as we grow up, what we’ll see is the hand will go up to the face but at the last minute there’ll be a diversion, like an ear-tug or an eye rub”. “If you have an itchy nose it will usually need scratching, but deceptive people will give it a cursory touch.”

Van Aperen notes that we have glands in the tip of our nose which, when we lie, secrete a chemical that makes it itchy. “So the Pinocchio theory is not that far removed from the truth”.

He warns that sometimes, however, body language can be misconstrued as a sign of lying. Loss of eye contact alone, for example, does not always indicate deception – often people avert their eyes when they’re trying to recall something. For this reason, it’s important to “benchmark” a behaviour (for example by watching how a person reacts to a question requiring them to use their memory) and then look for deviations from that.

Verbal cues
A person’s words often bring them unstuck, “but often we don’t listen to what they’re saying”, says Van Aperen. It’s important to remember that “people won’t often lie to you but they’ll be omissive, evasive and dismissive. What will happen is they’ll only lie when they’re confronted and they have no other option”.

Verbal signs of deception can include:

• “fillers” – ums and ahs and other superfluous words used to fill the gap while the brain tries to think of the next part of the lie;
• qualifying statements – a deceptive person will deny a narrow part of the interviewer’s question.

• “What they say is factually correct, but they don’t answer the question. That’s what deceptive people do; they’ll find some small issue that they can hang their hat on and know they can hang their hat on because they’re telling the truth. Often the problem is the question itself.”

• evasive or dismissive answers – for example: “I’m pretty sure they should be” instead of “yes”.

Van Aperen says that when using behavioural interviewing, interviewers should ensure they carefully listen to the candidates’ language. For example, if after being asked “give me an example of a time when…” the candidate uses words like “I would have…”, they are not saying what they have done.

“When someone tells you what they would do, it doesn’t tell you what they have done previously. It’s really an opinion; they probably have no experience in dealing with that situation.”

Clear questions the key to avoiding deception
In any interview, if your questions are not clear and concise, a deceptive person is going to find wriggle room through them,” Van Aperen says. “There should be no room for misinterpretation or ambiguity.”

The most important thing to remember, he says, is: “If you ask a question and you don’t get an answer back to that question, go back and ask the question again until you’re satisfied with the answer.”